/** S - (a_max - a_min) = pre_b(j) - a(j) - (pre_b(i - 1) - a(i)) **/ #include <bits/stdc++.h> using namespace std; int n; struct Data { long long size, value; bool operator < (const Data &other) const { return (size < other.size); } }; #define MAX_N 500500 Data d[MAX_N]; int main() { ios_base::sync_with_stdio(false);cin.tie(nullptr); cin >> n; for (int i = 1; i <= n; ++i) cin >> d[i].size >> d[i].value; sort(d + 1, d + 1 + n); for (int i = 1; i <= n; ++i) d[i].value += d[i - 1].value; long long ans = 0, pref = d[1].size; for (int i = 1; i <= n; ++i) { ans = max(ans, d[i].value - d[i].size - pref); pref = min(pref, d[i - 1].value - d[i].size); } cout << ans; return 0; }